山黧豆根系对H2O2诱导氧化胁迫的生理应答

以水培7d苗龄的山黧豆幼苗为材料,向水培溶液中施加不同浓度H2O2处理山黧豆幼苗24h,分析山黧豆根系受氧化胁迫的程度与抗氧化系统的应答特征,以揭示山黧豆对氧化胁迫的耐受机制。结果显示:(1)随外源H2O2处理浓度的不断增加,山黧豆幼苗侧根的数目无显著变化,而其根的鲜重则显著降低。(2)同时,根系组织的内源H2O2染色范围和程度显著增高,但根尖区域始终保持较低水平的H2O2;相反,O-·2染色范围和程度明显减少,根尖区域却始终保持较高水平的O-·2。(3)同期根系抗坏血酸(ASC)含量及过氧化氢酶(CAT)、过氧化物酶(POD)与抗坏血酸过氧化物酶(APX)的活性均表现出了先升高后降低的趋势,而超氧化物歧化酶(SOD)一直表现为持续上升的趋势。研究表明,在外源H2O2胁迫条件下,山黧豆根系O-·2的积累可能与其生长和活力呈正相关,而根系H2O2的积累则与其受氧化胁迫程度呈正相关;低浓度的H2O2处理可以提高山黧豆抗氧化系统对体内活性氧的清除能力。     

外源NO对2+胁迫下小桐子幼苗抗氧化能力的影响

为探讨外源一氧化氮(NO)供体硝普钠(SNP)对铜(Cu2+)胁迫的缓解效应,该试验以小桐子幼苗为材料,先通过小桐子幼苗根茎生长指标的变化筛选出后续实验适宜的SNP(0.2mmol/L)和Cu2+浓度(90mmol/L),再进一步考察SNP预处理对Cu2+胁迫下幼苗脯氨酸(Pro)和丙二醛(MDA)的含量及抗氧化酶活性的影响。结果显示:(1)Cu2+处理能诱导小桐子幼苗叶片中Pro和MDA含量显著升高,且过氧化氢酶(CAT)、超氧物歧化酶(SOD)、愈创木酚过氧化物酶(POD)及抗坏血酸专一性过氧化物酶(APX)的活性增强。(2)用SNP预处理能显著提高Cu2+胁迫下幼苗叶片Pro的含量,进一步增强叶片中CAT、SOD、POD和APX活性,降低MDA的含量。研究表明,0.2mmol/L的SNP能够通过提高小桐子幼苗的抗氧化酶活性和游离脯氨酸含量来增强其抗氧化胁迫能力,从而显著缓解Cu2+胁迫对幼苗造成的氧化伤害,维持其正常生长发育。     

外源过氧化氢对小麦水分胁迫伤害的防护作用研究

采用营养液水培的方法,研究外源过氧化氢(H2O2)对10% PEG6000(聚乙二醇)水分胁迫引起小麦幼苗脂质过氧化伤害的防护作用。结果表明,0.05μmol·L-1H2O2能够缓解水分胁迫对小麦幼苗生长的抑制效应,使幼苗株高、根长和单株干重显著增加,并提高受旱小麦叶片超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)的活性及谷胱甘肽和抗坏血酸的含量,降低丙二醛(MDA)含量和超氧自由基(O2-.)产生速率。说明外源H2O2可抑制水分胁迫引起小麦幼苗脂质过氧化作用,增强小麦的抗旱性。     

H_2S对干旱胁迫下白三叶幼苗抗氧化防御能力的影响

以‘拉丁诺’白三叶(Trifolium repens cv.‘Ladino’)为试验材料,研究外源H2S处理对PEG6 000(聚乙二醇)模拟干旱胁迫下白三叶叶片相对含水量(RWC)、膜脂过氧化、活性氧成分、抗氧化酶、抗坏血酸-谷胱甘肽循环代谢和非酶抗氧化物质的影响,以揭示H_2S调控白三叶抗旱性的生理机制。结果显示:(1)0.2 mmol/L的外源NaHS(H_2S供体)能显著提高干旱胁迫下白三叶的叶片相对含水量,维持显著较低的电解质渗透率(EL)和丙二醛(MDA)含量。(2)与直接干旱胁迫相比,干旱胁迫下外源添加NaHS处理的白三叶叶片内超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性显著增强,抗坏血酸-谷胱甘肽循环代谢中关键酶抗坏血酸过氧化物酶(APX)、脱氢抗坏血酸还原酶(DHAR)、单脱水抗坏血酸还原酶(MDHAR)和谷胱甘肽还原酶(GR)活性及其抗氧化中间产物抗坏血酸(AsA)、谷胱甘肽(GSH)含量也显著提高。(3)叶片类黄酮、总酚和原花青素的含量在一定的胁迫时间范围内亦显著增加,并伴随着活性氧成分O_2~(-·)产生速率和H_2O_2水平降低。研究认为,外源H2S能通过促进干旱胁迫下白三叶体内的多重抗氧化防御能力来提高其幼苗的抗旱性。     

一氧化氮(NO)对镉胁迫下小麦幼苗氧化损伤的影响

为探讨一氧化氮(NO)对重金属镉胁迫后小麦幼苗氧化损伤的影响。采用营养液水培法,以"晋麦8号"为材料,一氧化氮供体硝普钠(SNP),NO清除剂牛血红蛋白(Hb)及SNP类似物亚铁氰化钠(SF)分别处理小麦幼苗,研究NO在镉(Cd)胁迫下对小麦幼苗抗氧化系统的影响。结果显示,SNP处理可以缓解镉胁迫对幼苗生长抑制,显著增加可溶性蛋白、叶绿素和GSH含量,减少丙二醛(MDA)和过氧化氢(H2O2)的含量,并降低超氧阴离子(O2·-)产生速率、可溶性糖和脯氨酸的积累。而NO清除剂牛血红蛋白(Hb)处理使镉胁迫对小麦幼苗的毒害增强,SNP类似物亚铁氰化钠(SF)处理则没有缓解效应;进一步实验发现,SNP降低了镉胁迫下超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、谷胱甘肽还原酶(GR)和抗坏血酸过氧化物酶(APX)等抗氧化相关酶的活性,减轻了镉胁迫的氧化损伤。NO可以通过调节抗氧化酶系统来缓解Cd对植物的毒害。     

一氧化氮对盐胁迫下小麦幼苗根生长和氧化损伤的影响

0.05和0.10 mmol/L一氧化氮(NO)供体硝普钠(sodium mtropmsside,SNP)处理明显减轻NaCl浓度为150 mmo1/L左右的盐胁迫对小麦幼苗根生长的抑制效应,其中0.05mmol/L的SNP效果最明显;0.30mmol/L以上的SNP处理对根抑制无明显缓解作用;当NaCl浓度大于300 mmol/L时,各种浓度的SNP均不能减轻盐胁迫对根生长的抑制.以N O清除剂血红蛋白(hemoglobin,Hb)以及NOx-,K3Fe(CN)6等为对照,观察到0.05 mmol/L的SNP能不同程度地提高150mmo/L盐胁迫下小麦幼苗根尖细胞中超氧化物歧化酶(SOD)、过氧化物酶(POD)和抗坏血酸过氧化物酶(ascorbateperoxidase,APX)活性,明显降低MDA、H2O2和O2-.的积累,阻断盐胁迫诱导的根尖细胞DNA片段化,表明NO能有效缓解盐胁迫引起的小麦幼苗根尖细胞的氧化损伤.     

外源H_2S对NO_3~-胁迫下番茄幼苗生理生化特性的影响

采用营养液水培方法,通过外源施加H2S供体NaHS(100μmol/L),研究了信号分子H2S对100mmol/L NO3-胁迫下番茄幼苗生理生化特性的影响。结果表明:(1)NO3-胁迫下,随着处理时间的延长,番茄幼苗的株高、根长、鲜重和干重显著降低,叶绿素(a、b)含量、净光合速率、气孔导度、蒸腾速率均显著降低,而胞间CO2浓度以及丙二醛(MDA)、H2O2含量增加,超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)和抗坏血酸过氧化物酶(APX)活性显著降低,抗坏血酸(AsA)和还原性谷胱甘肽(GSH)含量显著降低。(2)与NO3-胁迫处理相比,外源NaHS处理1、3、5d后,番茄幼苗的株高、根长、鲜重和干重显著增加,叶绿素(a、b)含量、净光合速率、气孔导度、蒸腾速率均显著升高,而胞间CO2浓度显著降低;MDA和H2O2含量降低,SOD、POD、CAT和APX活性显著增强,AsA和GSH含量显著增加,而且幼苗的硝酸还原酶、谷氨酰胺合成酶、谷氨酸合酶的活性显著增强;L-半胱氨酸脱巯基酶活性和内源H2S含量增加。研究认为,外源H2S可能通过提高抗氧化物酶的活性和增加抗氧化物质含量来缓解NO3-对番茄幼苗造成的伤害,从而增强其对NO3-胁迫耐性。     

外源-氧化氮供体硝普钠对黑麦草幼苗耐碱性的影响

采用营养液砂培方法,研究外源一氧化氮(NO)供体硝普钠(SNP)对NaHCO3胁迫下黑麦草幼苗生长、活性氧代谢和渗透溶质积累的影响.结果表明:60 μmol·L-1 SNP能够缓解100 mmol·L-1NaHCO3胁迫对黑麦草幼苗生长的抑制作用,减缓NaHCO3胁迫导致的叶片O2产生速率、H2O2和丙二醛(MDA)含量的增加,提高NaHCO3胁迫下幼苗叶片超氧化物歧化酶(SOD)、过氧化物酶(POD)、抗坏血酸过氧化物酶(APX)、质膜H+-ATP酶的活性和谷胱甘肽(GSH)、可溶性糖、可溶性蛋白质和脯氨酸的含量及K+/Na+比,降低过氧化氢酶(CAT)活性和抗坏血酸(AsA)含量,对游离氨基酸含量影响不大.上述结果表明,NO可能通过激活抗氧化系统活性、促进渗透溶质积累和改善Na+、K+平衡等缓解碱胁迫对幼苗的伤害,从而提高黑麦草的耐碱性.     

外源硝酸钙对盐胁迫下黄瓜幼苗叶片抗氧化系统及膜质子泵活性的影响

采用营养液水培法,以较耐盐黄瓜品种"新泰密刺"为试验材料,研究了叶面喷施硝酸钙对盐胁迫(NaCl65mmol·L-1)下黄瓜幼苗活性氧、谷胱甘肽-抗坏血酸循环(GluAsA)中抗氧化酶和抗氧化物质及膜质子泵活性的影响。结果表明:叶面喷施硝酸钙能够显著降低盐胁迫下黄瓜幼苗叶片超氧阴离子(O.2-)产生速率和丙二醛(MDA)含量;显著提高盐胁迫下黄瓜幼苗叶片抗坏血酸过氧化物酶(APX)和脱氢抗坏血酸还原酶(DHAR)等酶活性、抗氧化物质抗坏血酸(AsA)含量、AsA/DHA和GSH/GSSG比值及质膜和液泡膜H+-ATPase和H+-PPase活性。表明外源硝酸钙通过提高Glu-AsA抗氧化系统和膜质子泵活性,降低活性氧对叶片的伤害,增强了植株抗氧化能力和对离子的区域化,进而提高植株盐胁迫耐性。     

燕麦幼苗对盐胁迫的响应及过氧化氢对响应的调节

为了探讨‘定莜6号’燕麦对盐胁迫的生理生化响应及H2O2的调节作用,采用水培方法,研究外源H2O2对盐胁迫下燕麦活性氧代谢、渗透溶质积累和Na+、K+平衡的影响。结果表明:小于100 mmol·L-1Na Cl未对‘定莜6号’幼苗的生长造成明显影响,150 mmol·L-1及以上浓度Na Cl使幼苗干重和叶片K+/Na+显著降低,O2-·产生速率、H2O2、丙二醛(MDA)、可溶性蛋白质和脯氨酸含量及过氧化氢酶(CAT)、质膜H+-ATP酶活性明显提高,但抗坏血酸(ASA)和谷胱甘肽(GSH)含量变化不大;外施5μmol·L-1H2O2可显著缓解150 mmol·L-1Na Cl胁迫对燕麦幼苗生长的抑制作用,使燕麦叶片超氧化物歧化酶(SOD)、抗坏血酸过氧化物酶(APX)和CAT活性及H2O2、GSH含量明显提高,O2-·产生速率和MDA含量显著降低;5μmol·L-1H2O2还提高了150 mmol·L-1Na Cl胁迫下燕麦叶片可溶性蛋白质、可溶性糖、有机酸和脯氨酸含量及质膜H+-ATP酶活性和K+/Na+,降低了游离氨基酸含量;表明外源H2O2可调控燕麦幼苗活性氧代谢和渗透溶质积累,维持K+、Na+平衡,从而增强耐盐性。     

六种藓类植物茎的比较解剖学研究

通过对6种藓类植物,即褶叶青藓(Brachythecium salebrosum(Web.et Mohr.)B.S.G.)、湿地匐灯藓(Plagiomnium acutum(Lindb.)Kop.)、侧枝匐灯藓(Plagiomnium maximoviczii(Lindb.)Kop.)、大凤尾藓(Fissidensnobilis Griff.)、大羽藓(Thuidium cymbifolium(Doz.et Molk.)B.S.G.)和大灰藓(Hypnum plumaeforme Wils.)嫩茎和老茎的石蜡切片和显微观察发现,同一藓类植株的嫩茎和老茎,茎结构稳定,不同种藓类植物茎横切面具有不同特征.植物体茎横切面形状、表层细胞的层数、细胞大小和细胞壁厚薄、皮层细胞大小和形状、中轴的有无以及比例等特征可以作为藓类植物的分科分类依据之一.     

Cause of Senescence of Nine Sorts of Flowers

The levels of endogenous phytohormones and respiratory rate in nine sorts of flowers such as Cymbidium faberi Rolfe, Nopalxochia ackermannii Kunth and others were investigated both at full bloom and senescence and meanwhile the effect of exogenous phytohormones on prolonging the blossoms and promoting ethylene production were tested. There is a high content of endogenous ethylene in all the long-lived flowere, about 3–16 folds higer than the short-lived ones. There is a high level of ABA at full blooming flowers of short-lived flowers, in which there is no or only some cytokinins in it, but the ratio of CTK (6BA+zeatin)/ABA is smaller(l.7). The endogenous ABA reached a much higher level at senescence in all nine sorts of flowers, so it is reasonable to consider that it is ABA which plays an important role of regulation in controlling flower's senescence. There is a much higher level of GA3 and zeatin in the long-lived flowers which is not demonstrated in the shortlived ones. The respiratory rate is one of the factors controtling the longevity of flowers, but it does not play a decided role. Application of 6BA and zeatin prolongs distinctly orchid’s longevity, however exogenous IAA through the promotive action on ethylene production, evidently extends the longevity of the flowers of the Nopalxochia ackermannii Kunth.     

龙胆科药用植物化学成分的研究现状

龙胆科植物在我国的分布范围很广,且多数为药用植物,其多数种属的药用植物,至今其化学成分尚未被系统研究。综述了目前龙胆科药用植物的化学成分的研究现状及一般提取方法,对近年来发现的环烯醚萜及裂环烯醚萜类化合物进行了总结,为本科药用植物的更深入研究提供了参考。     

真菌类遗传学分析的知识结构教学

本文以认知结构理论为指导,讨论了真菌类遗传分析与高等动植物遗传分析的内在联系,认为利用这种内在联系进行教学可收到好的效果并说明了作者的具体教学过程。 Abstract:In the paper, the relationship between genetic analysis of Fungi and genetic analysis of high animal and plant was discussed.A good results were obtained when we adopted this method in the teaching.     

The effects of glutamine of the maintenance of embryogenic cultures of Cryptomeria japonica

Summary Embryogenic tissues of sugi (Cryptomeria japonica) were induced on a modified Campbell and Durzan (CD) medium containing 1 μM 2,4-dichlorophenoxyacetic acid (2,4-D) and 600 mg l⁻¹ glutamine, and subcultured in the medium of the same composition for over 1 yr. This resulted in a mixed culture of embryogenic and non-embryogenic cells. When embryogenic cells were isolated and cultured independently, their capacity to form embryogenic aggregates was lost. Thus, the non-embryogenic cells present within a mixed culture system were essential to the formation of embryogenic aggregates. When embryogenic tissues were isolated and cultured independently on a high glutamine-containing (2400 mg l⁻¹) medium, dry weights and endogenous levels of glutamine increased, and the tissue could generate a large number of embryogenic aggregates. Amino acid analysis of embryogenic and non-embryogenic cells from the maintenance culture indicated a higher level of glutamine was present in the latter. The high endogenous level of glutamine in the non-embryogenic portion of mixed cell masses may be the supplier of glutamine for maintaining the embryogenic property of the tissues.     

Specificity of action of piperidylcholine derivatives as substrates of cholinesterases of various origin

The review deals with study of enzymologic properties of a novel highly specific acetylcholinesterase substrate, N-(β-acetoxyethyl) piperidinium iodomethylate (“piperidylcholine”), and its 30 derivatives that were tested as effectors of cholinesterases of mammals and various species of Pacific squids. It was proven for the first time that responsible for specificity of action was structure of cyclic ammonium grouping of the alcohol part of molecule of the ester substrate. Analysis of specificity is performed based on enzymatic hydrolysis parameters—activity of catalytic center of cholinesterases and bimolecular constant of the reaction rate that are determined at optimal and low substrate concentrations. Among the specially synthesized group of thioester compounds there is revealed one more highly specific acetylcholinesterase substrate—N-(β-acetoxyethyl) piperidinium.     

Photoregulation of seed germination of wild-type and of an aurea-mutant of tomato

Seed germination of an aurea mutant of tomato ( Lycopersicon esculentum Mill.) is promoted by continuous irradiation with red, far-red or long-wavelength far-red (758 nm) light as well as by cyclic irradiations (5 min red or 5 min far-red/25 min darkness). Far-red light applied immediately after each red does not change the germination behaviour. Seed germination of the isogenic wild-type, cv. UC-105, is promoted by continuous and cyclic red light while it is inhibited by continuous and cyclic far-red light and by continious 758 nm irradiation. Far-red irradiation reverses almost completely the promoting effect of red light. The promoting effect (in the aurea mutant) and the inhibitory effect (in the wild-type) of continuous far-red light do not show photon fluence rate dependency above 20 nmol m⁻² s⁻¹. It is concluded that phytochrome controls tomato seed germination throgh low energy responses in both the wild type and the au mutant. The promoting effect of continuous and cyclic far-red light in the au mutant can be attributed to a greater sensitivity to P_fr.     

医疗机构合理用药评价模型的构建研究

目的 针对医疗机构的合理用药水平进行评价研究。方法 根据医疗机构合理用药的具体要求,构建医疗机构合理用药评价指标体系,采用基于模糊群决策的方法和多指标评价分析法构建医疗机构合理用药评价模型。结果 构建了基于模糊群决策的医疗机构合理用药评价模型,并通过实例分析证明了评价模型的可行性。结论 建立的基于模糊群决策的医疗机构合理用药评价模型能够对医疗机构的合理用药水平进行科学评价,为提高医疗机构合理用药水平奠定基础。